1. Field of the Invention
The present invention relates to compositions and articles of manufacture for providing anti-static and softening benefits to fabrics in an automatic clothes dryer. More specifically, the present invention relates to anti-static and softening compositions and articles made therefrom which exhibit excellent storage stability.
2. Description of the Background
Numerous compositions have been proposed for incorporation into so called "fabric softeners" used in automatic clothes dryers. Typically, softening agents and anti-static agents are dispensed into the dryer from a suitable substrate on which the anti-static/softening compositions are carried. For example, a highly preferred substrate for use in dispensing the anti-static/softening compositions comprises a sheet of a flexible paper or woven or non-woven cloth on which the compositions have been deposited or impregnated.
Fabric "softening" is generally understood to be that quality of the treated fabric whereby its handle or texture is smooth, pliable and fluffy to the touch. Along with imparting softness, it is desirable that the softener/anti-static composition reduce the "static cling" of the treated fabrics. Static cling is the phenomenon of one fabric adhering to another or to parts of itself as a result of static electrical charges located on the surface of the fabric. It can also involve the adherence of lint, dust and other similarly undesired substances to fabric due to these static charges. Static cling is noticeably present in fabrics which are freshly washed and then dried in an automatic dryer. By softening and reducing the static cling of a fabric, it becomes more comfortable to wear, easier to iron and generally possesses fewer hard to iron wrinkles.
It is known, as taught in U.S. Pat. No. 4,209,549, that certain hygroscopic, highly ethoxylated surfactants can be employed as anti-static agents and that such surfactants can be advantageously admixed with mixtures of glycerides and glyceride-fatty alcohol mixtures to enhance fabric softening properties. However, heretofore mixtures of such ethoxylated surfactants, glycerides and fatty alcohols have not been used commercially because of the fact such mixtures tend to suffer from poor stability at normal storage temperatures i.e. temperatures generally encountered in warehouses and other such storage facilities which generally are not provided with air conditioning to maintain controlled temperature conditions. This lack of storage stability is evidenced by a tendency of the substrate upon which the composition is carried to cling or stick to itself making it difficult to separate individual sheets of the substrate from contiguous sheets whether the sheets be stacked or in a dispensing box such as are commonly used to dispense facial tissues one at a time. In the most common means of marketing dryer sheets, the individual sheets are detachably attached to one another and are in a roll. Lack of storage stability makes it difficult to unravel a sheet from the roll because of the sticking together of the successive windings of the roll. Moreover, lack of storage stability results in dryer sheets having an uneven distribution of softening composition, reducing their effectiveness.